1. Field of the Invention
The present invention relates generally to a suspension control system for an automotive vehicle. More specifically, the invention relates to a technologies for adjusting wheel load distribution depending upon wheel slippage for stability of vehicular driving behavior.
2. Description of the Background Art
Japanese Patent First (unexamined) Publication (Tokkai) Showa 62-275814 discloses a sort of an active suspension system which acts in active manner for suppressing vehicular body attitude change according to vehicle driving condition and thus achieves both of vehicular riding comfort and driving stability. Such prior proposed suspension control system adjusts wheel load distribution in order to suppress vehicular body attitude change, such as pitching and rolling. Particularly, the disclosed invention in the prior proposal concerns anti-rolling suspension control for adjusting wheel distribution for left and right side wheels so as to appropriately adjusting cornering force. Namely, according to the prior proposal, wheel load distribution is so adjusted as to resist against yawing moment which is induced by lateral acceleration generated by driving and braking force exerted on the vehicle. Such prior proposed system is successful in accomplishing minimization of variation of cornering force and whereby providing better cornering performance of the vehicle.
On the other hand, such prior proposed system still holds a drawback to be improved for providing better balance or higher stability of the vehicle. Namely, in the prior proposal, road surface friction or road/tire traction which reflects wheel slippage at each individual wheel, has not been taken into account in controlling the wheel load distribution. The factor of road/tire traction becomes particularly important for providing satisfactorily high vehicular driving stability during cornering or braking at a condition close to critical points. Namely, when traction is relatively low, there is a possibility of breaking of traction for causing abrupt vehicular attitude change for falling the vehicle in unstable condition.